[wings] Add first steps to Valkyrie persistence, protected by guard
[wings] Add first steps to Valkyrie persistence, protected by guard

Implements most of what's required from a basic save. Some behavior is missing,
so a guard clause is added so the code is never called, but as a switch to make
further progress easy to gague.

ht: da39a3ee5e6b4b0d3255bfef95601890afd80709@revgum

samvera/hyrax,samvera/hyrax,samvera/hyrax,samvera/hyrax